US 2008/002328 A1 discloses an electrical connection between protuberances of two busbars. The protuberances are provided at parallel longitudinal edges of the busbars and each include the two conductors and the insulation layer of the respective busbar. In the area of each of these protuberances, one of the two conductors is twice bent by 90° and thus offset away from the other conductor. As a results, the two conductors are parallel at a free distance with regard to each other at the free end of each protuberance. A shaped body of electrically insulating material is arranged between the two conductors in the area of both protuberances. Electrically conductive contact elements made as metal plates are arranged on those sides of the conductors facing away from the shaped body. Two threaded rods are fixed to one of the two metal plates which extend through holes in the shaped body and in the other metal plate. In the area of the other metal plate, the threaded rods are enclosed by insulating bushings. These insulating bushings are supported at that side of the other metal plate facing away from the shaped body via a radial flange and serve as abutments for nuts threaded onto the threaded bars. By means of these nuts, the two metal plates are forced together without providing an electrical contact between them. The surfaces of the metal plates facing the conductors may be structured by means of small grooves running perpendicular to the longitudinal edges to enhance the electric contact between the metal plates and the conductors.
When the electrical connection known from US 2008/002328 A1 has to conduct high currents flowing from one busbar to the other in operation of capacitor banks, like for example as buffer capacitances in an inverter feeding electric energy from a photovoltaic generator into an AC power grid, it quickly reaches higher temperatures. At these higher temperatures, the force applied between the conductive contact elements by means of the nuts may get lost due to the lower temperature stability of the insulating bushings made of plastic. As a result, the two-dimensional electric contact between the contact elements and the conductors contacted by them may get lost. This particularly applies if the longitudinal edges of the two busbars and/or the two conductors of each busbar are not exactly parallel and may thus only be forced into a sufficient two-dimensional electric contact with the metal plates by a considerable force. For this reason, complicated contact mediating elements have to be arranged between the contact elements and the conductors, like they are for example known from EP 0 716 474 A1, to permanently ensure the desired electric contacts. These contact mediating elements are also used, for example, to make forked plugs for a pluggable connection of current rails in current converters in rail vehicles, and they consist of elastically deformable structures made of sheet metal. With very high currents to be conducted, these contact mediating elements quickly reach their physical limits and overheat due to their comparatively small conductive sheet cross sections.
There still is a need for an electrical connection between two busbars made of flat conductors and of an insulating layer arranged between the two conductors at parallel longitudinal edges of the two busbars which provides for an improved electrical contact between the two busbars, particularly with regard to its thermal stability.